Патент USA US2118266код для вставки
May 24, 1938. 2,118,266 c. H. NORDELL SEWAGE TREATMENT Filed June 29, 1956 o 3 New . MM, ” l 5, 2,118,266 rPatented May 24, 1938 UNITED- STATES’ - PATENT OFFICE’ 2,118,266 SEWAGE TREATMENT ' Carl H. Nordell, Chicago, 111., assignor to Advance Engineering Company; Chicago, 111., a corpora-, tion of Illinois Application June 29, 1936, Serial No. 87,885 4 Claim. (CL- 210-8) This invention relates to ‘the treatment ,of. ditioned state becomes immediately available for sewage, and particularly. to the treatment of sewage with the so-called activated sludge process ' in which the ‘incoming sewage is mixed with sludge resulting from the process and the mixed liquid is subjected to aeration. _ J In all sewage'treatment systems the amount of sewage to be treated and the strength or concen tration of the sewage is subject to very considere 10 able ?uctuations. Rainstorms cause consider able changes of volume and-strength in the case _of combined surface water-and sewage systems. Changes in volume and strength occur periodical sewage aeration when a peak load needs to be treated. Conversely, when a weak or light oxida tion load .is being received and a charge of pre conditioned sludge is being accumulated, only part of the aerating tank system may be used for sewage treatment, a condition which is particu larly adapted for e?icient operation. ,The invention will more fully be understood from the following description of- a preferred 10 ,method' of- operation as practiced in a suitable apparatus illustrated in the accompanying draw ing in which; Figure 1 is a diagrammatic sectional plan view Thus, during any twenty-four hour period of a sewage treatment apparatus, and the strength of sewage varies within' very wide 15 Fig. 2 is a sectional detail view taken on the limits. During the night and early morning the ‘ incoming flow may be mainly water which drains l line 2--2 of Fig. 1. Referring to the drawing, the main aeration from the ground into the sewers. In the fore tanks are indicated by the reference numerals I0. noon the amount of excreta collected by the sys tem may attain peak proportions. Another factor These tanks are'connected in series and are ar which may give a peak load of short duration is ranged alongside each other.. It will be under ly. the delivery of trade wastes into the sewage sys tem. .. > In my copending application, Serial No. 41,741, ?led September23, 1935, I have described and claimed a method‘ of controlling the air supply for the effective treatment of sewage of any pre vailing strength and rate of supply. The present invention relates primarily to a 30 method in which the sludge admixed with the sewage ispreconditioned and controlled. Thus, generally stated in times of low load I accumulate a charge of sludge and maitnain it at a high de gree .of e?iciency by supplying an ‘appropriate amount of air thereto. In the preferred manner of operation I pass sludge continuously from the accumulating mass into admixture with the in coming sewage. When the sewage becomes stronger I may supply an extra quantity of sludge 40 to the‘incoming sewage. This extra quantity I deliver over a period of time‘ or practically im mediately depending upon- the nature of the change in the strength of the sewage. Thus, in the event of a daily periodic peak load of several 45 hours’ duration I add the extra quantity of pre conditioned supply of sludge gradually over several hours of time. In the case of a sudden change of strength due to the dumping of a ' large amount of trade wastes into the sewage sys tem, the additional amount of sludge may be brought 'into the aeration system practically in stantaneously. stood that this location of ' aeration tanks is merely one conventional arrangement which may . ‘ One of the important advantages of my new method lies in the fact that the tank in which 55 the sludge is accumulated and held in precon be employed. . ' , Each tank I0 is provided with a suitable aerator 25 II which maybe supplied with compresed air from a pipe I2, the supply to each aerator being controlled by valve l3 in the branch supply pipes |4_ . ., , An auxiliary tank I5 is provided which dis 30 charges into the inlet end of the first tank I0 through an opening IS. The tank I5 is provided with a suitable aerator II, which is supplied with air from a pipe I8, the supply being controlled by 35 a valve 19. The treated sewage passes from the outlet end of the last tank I0 through a pipe 20 to a settling tank 2|. I E?luent flows out of this tank by the over?ow pipe 22. Sludge is“ drawn from the bottom of the settling tank 2| by pump 23 and is 40 passed by pipe 24 to the inlet end of the tank IS. A suitable amount of sludge may be withdrawn continuously, or from time to time, by means of a pipe 25, and the amount of sludge in the system may be controlled by means of the valve 26. The tank l5 may be provided with one or more partitions 21 and 28 which separate it effectively into a plurality of compartments 29, 30 and 3|, ‘for example. The partitions 21 and 28 are pro vided with suitable openings 32, which are of adequate size to enable the sludge to ?ow from the inlet to the outlet end of the tank l5, while small enough to avoid any objectionable degree of ?ow in the opposite direction. The partition 21 is shown as permanently installed. The par 55 2 . 2,118,866 tition 28 is movable along the tank being pret ~ erably supported from a beam 33 which may rest upon the upper tank walls, as shown in Fig. 2. The sewage is supplied by the pipe 34. The pipe 34 is connected by valved branch pipes 35, 36, 31 and 38, to the inlet end of the first tank I ll, and to the compartments 3|, 30, and 29, re spectively. I . . ,1 ‘ I v In the normal operation of the-process, sludge 10 is accumulated in the tank l6 and is maintained _ - I‘ > . determined in the manner and with the apparatus described in my copending patent applica tions Serial No. 41,751‘?led September 23, 1935 and Serial No. 41,750 ?led September 23, 1935. Having thus described my invention, what, I 6 claim as new and desire to secure by Letters Pat ent of the United States is: I 1. The method of treatingvsewage which com prises subjecting sewage to aeration in an aerat ing zone, separating activated sludge from the preconditioned or in a highly active state by the , , treated sewage, returning a portion of said sludge ‘ expedient of subjecting it to a suitable degree of aeration by air supplied by pipe l8.v Thus, when the incoming sewage is “scant or weak, 15 it is delivered through the pipe 35 directly into the tanks Ill. The sludge supplied'by the pump 23 builds up in the compartments 29, 30 and 3|, a certain amount passing continuously through the opening l6 into the ?rstptank M, where it is 20 admixed with the incoming sewage. The quan tity of sludge builds up in the tank l5 until a static condition is attained, as much sludge pass ing out of the tank l5 as enters it. This grad ual increase of sludge supply to the aeration 25 tanks may, in some cases, be arranged to take care of certain diurnal changes of'quantity and strength 0! the incoming sewage. When a peak load is being received the amount of sludge nec essary for the eii'ective treatmentol' the sewage 80 is very high and all or a part 01' the sewage is diverted by one or more_of the pipes 36, 31 and 38 into the tank l5. It will be seen that a small supply of sewage into one of these pipes will give an immediate corresponding increase to the sludge supplied to the reaction chambers Ill through the opening l6. It a very heavy peak load arrives, due, for example, to the sud den discharge of a large amount of trade waste into the sewage system, all the sewage may be 40 diverted into the tank l5. Thus, the whole sew age supply may be diverted into the compart ment 3 I, with the result that all the sludge there in is immediately thrown into use. When this is done the compartment 3| serves as an aerating tank and thus temporarily augments the aera tion capacity of the system at the time that an increase of capacity is urgently needed. This procedure may be repeated successively with the other compartments 30 and 29, with the result 60 that the whole reserve supply of preconditioned sludge and the whole reserve aeration space of the tank I5 is throwninto action. It will be understood that the amounts of air supplied and the rate of‘ sludge supply will de 55 pend upon the volume of the incoming sewage and its strength. These factors may readily be to the aerating zone, accumulating a body of activated, sludge in a preconditioning zone, and diverting at least a part of the sewage into the preconditioning zone‘ and thereby displacing a 16 quantity of sludge into the aerating zone. '2. The method of treating sewage which com prises subjecting sewage to aeration in an aerat ing zone, separating activated sludge from the treated sewage, passing said sludge to a pre— 20 conditioning zone communicating with said aerating zone, and thereby displacing a corre sponding ‘volume of activated sludge into said aerating zone, and diverting at least a part of sewage into said preconditioning zone andv there by increasing the quantity of activated sludge displaced into the aerating-zone. - 3. The method of treating sewage which com prises subjecting sewage to aeration in an aerat ing zone, separating activated sludge from the treated sewage, returning a part of said sludge to the aerating zone, accumulating a body of activated sludge in a preconditioning zone, di verting at least a part of the sewage into the preconditioning zone and thereby displacing a further quantity of sludge into the aerating zone, and thereafter diverting thesupply of sewage directly into the aerating zone and accumulat ing a new supply of sludge in the precondition ing zone. 4. The method of treating sewage which com prises subjecting sewage to aeration in an aerat ring zone, separating activated sludge from the v treated sewage, passing said sludge to a pre conditioning zone communicating with said aerating zone, thereby displacing a supply of activated sludge into said aerating zone, divert ing at least a part of sewage into said precon ditioning zone and thereby increasing the quan tity of activated sludge displaced into the aerat ing zone, and thereafter'diverting the supply of sewage directly into the aerating zone‘and ac cumulating a’ new supply of sludge in the pre conditioning zone. CARL H. NORDELL.